Surgical gowns, drapes and the like protect surgically prepared areas of the skin from contamination and also protect surgeons and nurses against contamination through contact with unprepared or contaminated areas of patient's skin. In addition, surgical gowns should present a sterile barrier to protect patients from contamination through contact with the surgeon, and vice versa.
Liquid imperviousness of the gown or drape is recognized as an important property in assuring that the gown or drape presents a sterile surface and acts as a barrier to the passage of bacteria or virus. Body liquids and other liquids can permeate through the surgical gown or drape and contact the skin of the patient. Thus, bacteria and viruses, such as the AIDS virus, which are present on the surface of the gown or drape may be transported through the gown to the patient or the operating room personnel.
In addition to being liquid repellent and a bacteria and viral barrier, hospital gowns desirably present a non-glare outer surface, are nonlinting, possess antistatic characteristics and, not least importantly, are comfortable to wear.
It has been widely recognized that garments must be "breathable" to be comfortable. However, it is not necessary that air pass through the garment for it to be comfortable, only that water vapor from perspiration be transmitted from inside to outside so that undergarments do not become wet and so that a natural evaporative cooling effect can be achieved. Breathability and ability to transport interior moisture vapor to the external environment are used interchangeably herein. If a continuous film of hydrophilic material is exposed to air containing substantial water vapor on one side of the film, and to air containing less water vapor on the other side, the side of the film exposed to the higher water vapor concentration will absorb water molecules which diffuse through the film and are desorbed or evaporated on the side exposed to the lower water vapor concentration. Thus, water vapor is effectively transported through the film on a molecule by molecule basis. This property is known as "breathability".
One type of commonly used protective clothing is made from a polyolefin nonwoven substrate. While having reasonable properties for protection, garments constructed of this material are known to be very uncomfortable due to their inherent low moisture transmission characteristics, i.e their low breathability. Various attempts have been made to improve breathability of this nonwoven material. These efforts, however, result frequently in a more open structure of the nonwoven material and thus also simultaneously lower its protection value. Coatings on spun-bonded polyolefin have been employed to afford greater barrier protection to the `open` base structure of the nonwoven. However, the already inherently low moisture transmission characteristics of the spun-bonded material are even further reduced, simultaneously reducing the comfort of garments made by use of this technology.
Protective clothing in hospital operating rooms has been made of wood-pulp filled, spunlaced polyester, heavily treated with a water-repellent. Here again a compromise in properties must be reached. Greater comfort sacrifices maximum microorganism barrier protection and greater barrier protection lowers comfort. For instance, where hospital operating room gown products require superior protection from microorganisms over the base spun-laced polyester, a polyethylene film is usually laminated to the polyester. But, while achieving good barrier characteristics, moisture vapor transmission is substantially eliminated.
As seen from the foregoing, protection properties and comfort properties are traded off with one another. The present invention allows for both very desirable barrier protection characteristics while simultaneously achieving good moisture vapor transmitting characteristics; i.e. protection with comfort.